SH4_MMUCR
#define SH4_TLB_DISABLE *(volatile uint32_t *)SH4_MMUCR = SH4_MMUCR_TI
r = _reg_read_4(SH4_MMUCR);
r = _reg_read_4(SH4_MMUCR);
a = _reg_read_4(SH4_MMUCR) & SH4_MMUCR_URB_MASK;
_reg_write_4(SH4_MMUCR, 0); /* zero wired entry */
_reg_write_4(SH4_MMUCR, SH4_MMUCR_AT | SH4_MMUCR_TI | SH4_MMUCR_SQMD |